This invention relates to a method of supporting mine walls in a mine passageway and to a method of installing a mine stopping.
Mine stoppings are widely used in mine passageways to stop off the flow of air therethrough. A conventional metal stopping shown in U.S. Pat. No. 4,483,642 comprises a plurality of elongate extensible panels 7 extending vertically from the floor to the roof of the mine passageway and positioned in side-by-side relation across the passageway. (See FIG. 1 of the patent.) The mine walls of the passageway tend to shift over time (especially coal mine walls), generally moving closer together from the weight of the overburden. Shifting tends to cause cracking and sloughing off of large portions of the mine walls, which can result in the leakage of air past the aforementioned stopping. Such leakage increases the operating cost of a mine, since more fresh air must be pumped into the mine.
A conventional metal stopping as disclosed in the aforementioned patent is typically constructed by embedding ends of elongate bars 3 in the mine walls. The bars include two or more overlapping steel angles which are slidable relative to one another and held in place by ties or tape. (See FIG. 2 of the patent). The telescoping panels are positioned side-by-side so that they are in contact with the bars. An upper member 17 of each telescoping panel 7 is extended relative to a lower member 13 of the panel so that it engages the roof of the mine, and the upper and lower members are held in place by wire ties 9 secured to the bars 3.
The elongate bars of the conventional metal stopping provide little or no support to the mine walls. The ends of the bars are typically either embedded in holes in the walls or placed on shelf formations on the walls. In either case, the cross-sectional area presented by the ends of the bars is too small to provide significant lateral support to the walls. Moreover, since the frictional forces exerted by the wire ties is relatively small, the bars will slide relative to one another when subjected to relatively small compressive loads (e.g., 500 pounds are less). These loads are not sufficient to provide significant support to the walls, as during a mine convergence. Some prior art angles are bolted together so that the angles cannot slide. (See FIG. 1 of U.S. Pat. No. 2,729,064.) However, such non-yielding angles simply penetrate the mine walls upon convergence, thereby providing little or no support to the mine walls.
Among the several objects of this invention may be noted the provision of a method that inhibits cracking and sloughing off of opposing mine walls; the provision of such a method that reduces ventilation air leakage in the mine; the provision of such a method that provides yieldable support to the mine walls; the provision of such a method that is cost effective; and the provision of such a method which involves the installation of a mine stopping.
The present invention is also directed to a method of installing a mine stopping that is easy to perform, and the provision of such a method wherein the mine stopping is adapted to withstand significant loading caused by air pressure and by convergence of the mine walls.
In one aspect, the invention is directed to a method of supporting opposite first and second walls of a mine passageway including providing an elongate beam having opposite first and second ends and a longitudinal axis. The beam is configured to have substantial columnar strength for bearing a substantial longitudinal load applied to the beam generally longitudinally of the beam and substantial bending strength for bearing a substantial transverse load applied to the beam generally transversely of the beam. The method further includes selecting first and second locations on the first and second walls, respectively, providing suitable areas for supporting the first and second walls, and positioning the first end of the beam at the first location and the second end of the beam at the second location so that the beam extends between the first and second walls of the mine passageway. The method also includes securing the first end of the beam to the first wall at the first location and the second end of the beam to the second wall at the second location so that the beam is positioned for supporting the first and second walls.
In another aspect of the invention, a method of supporting opposite first and second walls of a mine passageway includes providing an elongate beam having opposite first and second ends and a longitudinal axis wherein each end of the beam has a bearing member thereon for bearing against a respective wall. The bearing member has a bearing surface area greater than the cross-sectional area of the beam. The beam is configured to have columnar strength for bearing a longitudinal load of at least 800 pounds applied to the beam generally longitudinally of the beam and bending strength for bearing a transverse load caused by an air pressure of at least two inches water gauge and applied to the beam generally transversely of the beam. The beam includes a central beam and a slide member slidable relative to the central beam. The method further includes selecting first and second locations on the first and second walls, respectively, providing suitable areas for supporting the first and second walls. The first end of the beam is positioned at the first location and the second end of the beam is positioned at the second location by sliding the slide member relative to the central beam to adjust the length of the beam to correspond to the distance between the first and second walls so that the beam extends between the first and second walls of the mine passageway. The bearing member of the first end of the beam is secured to the first wall at the first location and the bearing member at the second end of the beam is secured to the second wall at the second location so that the beam is positioned for supporting the first and second walls.
In yet another aspect of the invention, a method of installing a mine stopping between the first and second walls of a mine passageway includes providing an elongate beam having opposite first and second ends and a longitudinal axis. The beam is configured to have substantial columnar strength for bearing a substantial longitudinal load applied to the beam generally longitudinally of the beam and substantial bending strength for bearing a substantial transverse load applied to the beam generally transversely of the beam. The first end of the beam is positioned at a first location on the first wall and the second end of the beam is positioned at a second location on the second wall so that the beam extends between the first and second walls of the mine passageway. The method further includes securing the first end of the beam to the first wall at the first location and the second end of the beam to the second wall at the second location so that the beam is positioned to take a substantial longitudinal load. A stopping is erected to extend between the first and second walls after the beam has been secured to the walls. The erecting step includes securing the stopping to the beam so that a load applied to the stopping due to an air pressure differential across the stopping is transferred to the beam as a transverse load.
Other objects and features will be in part apparent and in part pointed out hereinafter.